Heat exchanger, exhaust gas recirculation system, and use of a heat exchanger

Abstract

A heat exchanger, particularly an exhaust gas heat exchanger, for transferring heat in two stages between a first fluid and second and third fluids that have different temperatures includes a block for separately conducting the first and second and third fluids in a heat transferring manner. The block encompasses a number of ducts through which the first fluid can flow, a first chamber of a high-temperature part through which the second fluid can flow and which accommodates the ducts, a second chamber of a low-temperature part through which the third fluid flows and which accommodates the ducts, and a housing in which the first and second chamber as well as the ducts are arranged. The first chamber and the second chamber are separated from one another by a separation area that is mounted in a groove.

What is claimed is: 
     
       1. A heat exchanger or an exhaust gas heat exchanger for two-stage heat exchange between a first fluid, a second fluid, and a third fluid having a different temperature, the heat exchanger comprising:
 a block configured for a separated and heat-exchanging conveying of the first fluid, the second fluid, and the third fluid; 
 a plurality of flow channels configured to allow the first fluid to flow therethrough; 
 a first chamber of a high-temperature part configured to accommodate the flow channels and configured to allow the second fluid to flow therethrough; 
 a second chamber of a low-temperature part configured to accommodate the flow channels and configured to allow the third fluid to flow therethrough; and 
 a housing, in which the first chamber, the second chamber and the flow channels are arranged; 
 wherein the first chamber and the second chamber are separated from one another by a separation area or a separating base that is mounted in a groove; 
 wherein the first chamber and the second chamber, lying one behind the other cross-sectionally, are arranged in the housing and each have flow channels arranged one behind the other; 
 wherein first fluid can flow sequentially and parallel in the same direction through the flow channels of the first and the second chamber; 
 wherein the flow channels of the first chamber and the second chamber are substantially identical; 
 and wherein the housing is made of two parts, wherein the housing parts are configured to be substantially identical and to directly abut each other, and 
 wherein the groove is formed by both housing parts and faces inwardly relative to the housing. 
 
     
     
       2. The heat exchanger according to  claim 1 , wherein the housing is made of a metal, an austenitic steel, aluminum, or alloys thereof, or wherein the housing is made of a non-metal, a plastic, a fibrous composite material, a ceramic, or a combination thereof. 
     
     
       3. The heat exchanger according to  claim 1 , wherein the separation area or the separating base is made of a metal, stainless steel, aluminum, or alloys thereof or wherein the separation area or the separating base is made of a non-metal, a plastic, hard rubber, fibrous composite material, a ceramic, or a combination thereof. 
     
     
       4. The heat exchanger according to  claim 1 , wherein the separation area or the separating base is mounted with a gasket in the groove or mounted using an adhesive, or is mounted in the groove using a soldered and/or welded joint or an edge region associated with the groove is coated with rubber and/or a polymer. 
     
     
       5. The heat exchanger according to  claim 1 , wherein the separation area is formed in the form of a separation area keeping the flow channels through-conducting and has passages that are chamfered. 
     
     
       6. The heat exchanger according to  claim 1 , wherein the separation area is formed of a plurality of separate separating elements, wherein one or more separating elements are each held in a flow channel, and wherein a separating element is configured of an annular bead surrounding a flow channel. 
     
     
       7. The heat exchanger according to  claim 1 , wherein the separation area or separating base comprises a plate mounted in the groove and including leakage paths in the groove between the first chamber and the second chamber. 
     
     
       8. The heat exchanger according to  claim 1 , wherein the first chamber is separated from the second chamber in a fluid-tight manner to prevent fluid flow from the first chamber to the second chamber. 
     
     
       9. The heat exchanger according to  claim 1 , wherein the separation area or separating base comprises a plate form-fittingly mounted in the groove.